Damn Wholesale Marine is fast - ordered yesterday, got it today.
Looks to be relatively cheap 22 guage 304 SS. Has horizontal grain, rather than a mirror finish, and does a great job of picking up and displaying fingerprints which won't wipe off. It measures 5.75" w by 4.5" h - small! As seen below, there's a .75" wide notch in the center to allow for an install around the bow eye, I don't believe that Wholesale marine carries the solid version without the notch. To install, one bends the plate to match the hull, and peels the backing of the 3M strip adhesive on the back of the scuff plate, (the entire back of the plate is covered except a 1/8" perimeter) and presses it in place. There's warnings about cleaning the area appropriately first. My boat's still in storage, but this scuff plate appears to be too small to provide complete protection. With the $9 and change I paid, I can't complain, but I doubt that I'm going to install this on the boat - it'd probably be fine for a smaller boat, too bad they don't make a bigger mirror finish version.

Here's the website:
http://www.keelguard.com/scuffbuster.html